Seed availability and insect herbivory limit recruitment and adult density of native tall thistle

dc.contributor.author	Russell, F. Leland
dc.contributor.author	Rose, Karen E.
dc.contributor.author	Louda, Svata M.
dc.date.accessioned	2011-09-19T21:53:52Z
dc.date.available	2011-09-19T21:53:52Z
dc.date.issued	2010-10
dc.identifier.citation	Russell, F. Leland, Karen E. Rose, and Svata M. Louda. 2010. Seed availability and insect herbivory limit recruitment and adult density of native tall thistle. Ecology 91: 3081-3093.	en_US
dc.identifier.issn	0012-9658
dc.identifier.uri	http://hdl.handle.net/10057/3790
dc.description	This is the authors' version of the work. It is posted here by permission of the publisher for personal use, not for redistribution. The definitive version was published in Ecology, v.91, 2010, pp. 3081-3093.	en_US
dc.description.abstract	Understanding spatial and temporal variation in factors influencing plant regeneration is critical to predicting plant population growth. We experimentally evaluated seed limitation, insect herbivory, and their interaction in the regeneration and density of tall thistle (Cirsium altissimum) across a topographic ecosystem productivity gradient in tallgrass prairie over two years. On ridges and in valleys, we used a factorial experiment manipulating seed availability and insect herbivory to quantify effects of: seed input on seedling density, insect herbivory on juvenile density, and cumulative impacts of both seed input and herbivory on reproductive adult density. Seed addition increased seedling densities at three of five sites in 2006, and all five sites in 2007. Insect herbivory reduced seedling survival across all sites in both years, as well as rosette survival from previous year’s seedlings. In both years, insecticide treatment of seed addition plots led to greater adult tall thistle densities in the following year, reflecting the increase in juvenile thistle densities in the experimental year. Seedling survival was not density-dependent. Our analytical projection model predicts a significant long-term increase in adult densities from seed input, with a greater increase under experimentally reduced insect herbivory. While plant community biomass and water stress varied significantly between ridges and valleys, the effects of seed addition and insect herbivory did not vary with gradient position. These results support conceptual models that predict seedling and adult densities of short-lived monocarpic perennial plants should be seed-limited. Further, the experiment demonstrates that even at high juvenile plant densities, where density-dependence potentially could have over-ridden herbivore effects on plant survival, insect herbivory strongly affected juvenile thistle performance and adult densities of this native prairie species.	en_US
dc.language.iso	en_US	en_US
dc.relation.ispartofseries	Ecology;91
dc.subject	Seed limitation	en_US
dc.subject	Insect herbivory	en_US
dc.subject	Cirsium	en_US
dc.subject	Ecosystem productivity	en_US
dc.subject	Population dynamics	en_US
dc.subject	Analytical approximation	en_US
dc.title	Seed availability and insect herbivory limit recruitment and adult density of native tall thistle	en_US
dc.type	Article	en_US
dc.rights.holder	Copyright 2010 by the Ecological Society of America